The present invention relates to a vehicle system and method for transmitting camera-based parameters along with video images from a video camera mounted on a vehicle to an endpoint therein for display.
In state of the art camera systems, more than image data from a camera must be received at an endpoint. In driver assistance arrangements, the cameras scan the environment for potential dangers and preemptively warn a driver. The arrangement requires that the relationship between real-world distances and pixel coordinates in an image is well known and accurate. Such arrangements require that each camera is calibrated individually and that the camera parameters are stored directly in each camera's non-volatile memory.
Additionally, for cameras used in driver assistance applications, functional safety is extremely important. To verify functionality of an image sensor, specific camera information is transmitted to a remote processing unit on the vehicle that validates the functional performance of the image sensor.
When implementing driver assistance functions in low-cost video camera hardware, some important issues arise. First, low-cost video camera systems are currently developed around VGA sensors that transmit video in an analog National Television System Committee (NTSC) format. Since NTSC video transmission was developed in the mid-20th century, it does not traditionally allow for embedding of metadata into the video stream (a feature that is often allowed in digital video transmission). For the NTSC format, the standard line resolution for a frame is 525 lines. A frame can be represented as 720 horizontal pixels by 486 vertical pixels. Compression algorithms, including digital video compression, allow for improved resolution.
Another analog video transmission format used in various countries is Phase Alternating Line (PAL) format. For the PAL format, the standard vertical line resolution is 576 lines for a frame. A frame is 720×576 pixels.
In automotive systems, most electronic control units (ECU's) have a connection to a vehicle bus (i.e. PSIS, DSI, SENT, CAN, FLEXRAY, LIN). However, in some multi-camera systems, such as surround view video systems, bus connections for each video camera are undesirable, due to the increased component and wiring costs. Thus, a different approach is contemplated.